## a question from math flt 012

Please solve the qs
If for a positive integer n, n! = (215 ) x (36) x (53) x (72) x (11) x (13) then the value of n is
it was on FLT 012... i got 13 in that test..how good is it
I am thinking about appearing CAT 07

There are many ways of approaching such qs . The best is to go with the given options
n! = (215 ) x (36) x (53) x (72) x (11) x (13)
as there are two 7s , it cant be 13 (two 7 means 7 , 14 =2x7)
as there are three 5s , it cant be 14 . so only two options are left 15 & 16.
Its given that the power of 2 is 15. so lets chk the power of 2 in 15! First
2 – 1
4 – 2
6 – 1
8 – 3
10 – 1
12 – 2
14 – 1
Total = 11 so it cant be 15. Now lets chk for 16
16 – 4
Total =15 and that’s what is given in the question. So ans n=16.

Thanks for the quick and complete explanation.

Thats perfect.
But i ll suggest to start such questions with the number which has the highest power. in this case 2 , so that you can save some time.
saloni about your score 13 - let me tell you its great considering the fact that you are just staring your preparation. all the qs in FLT are not just in the level of qs you get in typical FLTs.. they are real CAT standard qs.

thanks neerej for your remarks.
but i appeared that test w/o any time constraint..
can i have the answers for that test

I have spent a lot of time in this site in last 6 mnth but was never an active forum member as I was spending most of my time some where else.. But now I realized I have benefited a lot from the net w/o giving back much.. so now you can expect all sort of advices/in formations from me..

That’s the sole of any forum… to share knowledge and expertise.. I have always been a frequent posting member in all cat related forums – ims , time , cl … and it has helped a lot..i can say its best time pass

## soln 2 FLT

the best way 2 solve the quesstn z 2 go vid options n choosing the option from where to strt is also a big factor..start vid lets sy 15(coz v can judge easily whether the ans will fall above 15 or less than dat...if its above 15 v cn directly mark the option, which will save our tym otherwise v hav 2 calculate one mre iteration...this whole question vil take hrdly one min)...nw cum 2 choices...take 15! n break into this like 15*14*13.....*1 n cqalculate the powers of 2,3,5 nd so...u'l get ur ans